General Mathcad Design Considerations

[radair]

I've discussed this before, but I'll repost this thought here since it applies particularly to data analysis and Mathcad's philosophy of calculation management.

One of the things I want to do with Mathcad is create a document that can later be read like a book. As a book reader, I want to be able to read without being distracted by the next page/image/result taking a long time to display. With Mathcad, each time I open the document, it recomputes from the beginning which can be a real problem if it takes 10 or 20 minutes to analyze the data before the graph I really wanted to see gets generated. This is really annoying and means that I generate readable documents by creating pictures rather than active equations which makes the document far less useful.

Functions such as LeastSquaresFit should have the ability to cache their results and how they got them (such as started with these initial guesses) and save the cache with the worksheet. Upon opening, LeastSquaresFit should note that the initial conditions haven't changed, so the last results are still valid (with the caveat that the user can force a recalculate if desired to allow for algorithm modifications) and simply display the last results rather than recomputing them. Recomputing the same values each time the worksheet is browsed has no benefit for the end user.

Making Mathcad faster doesn't necessarily help the situation because I will just find harder problems that I currently don't do because they take too long.

I can think about the problem as one of data compression algorithms. The symbols in a Mathcad worksheet are a representation of compressed data, and the function execution is the data decompression algorithm. I think this algorithm should be modifed somewhat to allow decreased data compression and increased decompression speed.

Robert

[RichardJ]

I've said it before too, but I'll take the opportunity beat at this issue a bit. I agree with Robert 100% on this. I would like to have an option available when I go to "save as" that says "save current status of worksheet". If I check the box, it saves all the calculation results. If I hit [esc] to interrupt a calculation, then go to "save as", it should also save the intermeditate calculation results. I have had calculations that have taken hours to run, and I would happily take a large beating on file size if I avoid the "recalculation blues".

Richard

[IRstuff]

But don't you have an "out" right now?

If you wanted to save a "snapshot" of a particular configuration of a calculation, you could save as HTML or PDF, which would freeze the calculations in place.

Does the same sheet have to be "frozen" yet switchable to "live?"


TTFN,
Eden

[radair]

On 9/8/2003 2:35:32 PM, eden_mei wrote:
>But don't you have an "out"
>right now?
>
>If you wanted to save a
>"snapshot" of a particular
>configuration of a
>calculation, you could save as
>HTML or PDF, which would
>freeze the calculations in
>place.
>
>Does the same sheet have to be
>"frozen" yet switchable to
>"live?"
>
>
>TTFN,
>Eden

Yes, I want the switchable to live option. I currently use the out, but an interactive text option makes an even more useful document. As a teaching exercise, it's often useful to see how the results change when the problem is modified, but I don't derive any benefit waiting for the results to pop up when I'm first skimming the text. Computations containing nested integrals come to mind as one of the time consuming calculations that force me to cut short illustrations of diffraction physics.

Robert

[RichardJ]

On 9/8/2003 2:35:32 PM, eden_mei wrote:
>Does the same sheet have to be
>"frozen" yet switchable to
>"live?"

Yup. I want to be able to open a worksheet and change something that affects th last 10%, without having to recalculate the whole thing.

I wouldn't think that would be hard to do.

Richard

[ptc-1368288]

On 9/8/2003 3:05:24 PM, rijackson wrote:
>On 9/8/2003 2:35:32 PM, eden_mei wrote:
>>Does the same sheet have to be
>>"frozen" yet switchable to
>>"live?"
>
>Yup. I want to be able to open a
>worksheet and change something that
>affects the last 10%, without having to
>recalculate the whole thing.
>
>I wouldn't think that would be hard to
>do.
>
>Richard
________________________

We have that Richard, OK �
Save the sheet auto-calculation OFF.
When you open the sheet, if the last 10% is stand alone, click on the main entry function, F9.
It then continues down the end.
If we have the opposite: 10% at the top, I think it does the same, i.e: calculates the chained suite.

jmG

[RichardJ]

On 9/8/2003 4:50:51 PM, jmG wrote:

> if the last 10%
>is stand alone,

I am thinking of the case when the last 10% depends on the first 90%.

Richard